casual enough be prepared to talk about their products and what you like about the brand. you should be familiar with their products - what is your favourite product? What product do you like the most? how would you sell this product?

Applied in store, it was a 3 step interview process. First was a group interview. I managed to go through that and then had to go through a 1-on-1 interview. Didn't pass the 2nd interview.